Abstract Myocardial infarction (MI) is a leading cause of death worldwide, causing terminal loss of cardiomyocytes (CM). The search for regenerative therapy that can repair or replace lost CM remains a daunting challenge. The foremost issue is difficulty in procuring viable replacement cells. Heterologous sources are unattractive due to the potential for immunorejection. Harvesting healthy cells from a patient's damaged heart is invasive and poses severe risks. Finally, reprogramming somatic cells from other autologous sources can result in very low yields due to epigenetic memory, which favors reversion to the parental precursor cell type. A series of recent studies, however, has revealed that masseter muscle derived progenitor (MMP) cells share a common origin and have overlapping gene expression patterns with heart muscle. MMP can be isolated from highly accessible masseter muscles without mandible motor dysfunction and our preliminary data has shown that induced pluripotent stem cells (iPSC) derived from MMP yield the highest rate of CM differentiation as compared with other iPSC-derived somatic cells such as fibroblasts, mesenchymal stem cells, and trunk skeletal muscles. Therefore, MMP represent an ideal therapeutic candidate to maximize cardiogenic differentiation efficiency after cell transplantation in order to repopulate an infarcted heart region with a supply of autologous cardiac progenitor cells (CPC). At the same time, MMP avoid the common pitfalls associated with immunorejection, tumor formation, and reversion to an alternative epigenetic precursor. Aim 1 consists of in vitro studies to identify genetic biomarkers of MM to determine the optimal parameters for CM generation and characterize MM-derived Sca1+ cells with the highest CM differentiation potential. Aim 2 is designed to determine the mechanism by which microRNAs and transcription factor networks mediate MMP differentiation and the underlying cardiac potential of MMP as regulated by miR-128. Finally, Aim 3 focuses on the effects of implantation of a Sca1+-MMP-derived cardiovascular cell patch on the cardiac functions in a mouse MI model. Experiments will examine the fate of transplanted Sca1+-MMP derived from miR-128-null mice in vivo, determine any beneficial effects that result from cell engraftment, track the survival of miRNA-128 deficient Sca1+-MMP under ischemic conditions, and investigate the cell death-associated signaling pathway. These studies will provide new insights in both basic heart developmental biology and cell-based regenerative medicine.